Social Explorer; U.S. Census Bureau; Census of Population and Housing, 1980: Summary Tape File 3 [machine-readable data file] / conducted By the U.S. Bureau of the Census. Washington: Bureau of the Census [producer and distributor], 1982.

Total money income received in calendar year 1979 by all family members 15 years old and over, tabulated for all families. Family income differs from household income by excluding income received by household members not related to the householder, persons living alone, and others in nonfamily households. (Income of these unrelated persons along with income of persons living in noninstitutional group quarters is tabulated as income of unrelated individuals 15 years old and over.) See the definitions of "Income In 1979" and "Income Type" for a discussion of the sources of income recorded, means, medians, limitations, and comparability.

In income tables for families, the lowest income group (e.g., less than $2,500) includes families that were classified as having no 1979 income as defined in the census. Many of these were living on income "in kind," savings, or gifts; were newly created families: or were families in which the sole breadwinner had recently died or left the household. However, many of the families who reported no income probably had some money income which was not recorded in the census. Family income is recorded on public-use microdata in $10 intervals up to $75,000 or down to a net loss of $9,990 or more.

Median and mean family income figures are based on all families, unlike mean or median income figures for persons 15 years old and over, which exclude persons with no income. This item was derived on a sample basis.
Historical comparability: Family income distributions have been tabulated in each census since 1950. Family income has been replaced by household income distributions in certain tabulations for 1980.